Reversing turbine



March 6, 1934- J. H. DORAN REVERSING TURBINE Filed Sept. 50, 1933Dozlom,

W .W m nnn um e @Q m Two .6 J 9 b 6 Z Patented Mar. 6, 1934 Uisii'ihihTATE REVERSING TURBINE John H. Duran, Scotia, N. Y., assignor to GeneralElectric Company, a corporation of New York The present inventionrelates to reversing turbines such as are used for ship propulsion, moreparticularly to the kind of reversing turbines which comprise an aheadpart and an astern part exhausting into a common exhaust casing.

With the use of extremely high pressure, high temperature elastic fluidin modern turbine arrangements, particular attention must be paid to therelative expansion caused by the high temperatures between certain partsof the turbines. This applies particularly to the astern or reversingpart of a reversing turbine, which part usually comprises a singledouble-row bucket wheel. The flow of high temperature elastic fluidthrough this single wheel causes the same to be highly heated andtherefore expanded, whereas the massive, heavy shaft and other adjacentmembers, l ss exposed to the heat of the elastic fluid, are accordinglyless heated and expand less than the bucket wheel.

The object of my invention is to provide an improved construction andarrangement of the kind of reversing turbines above specified,particularly with respect to turbines which comprise two shafts, a shaftor drum for the ahead part and a stub fastened to the shaft for carryingthe wheel of the astern part.

For a consideration of what I believe to be novel and my invention,attention is directed to the following description and the claimsappended thereto in connection with the accompanying drawing.

In Fig. 1 of the drawing I have shown a sectional View, partly brokenaway, of a reversing turbine embodying my invention, and in Fig. 2 across sectional view along line 2--2 of Fig. 1.

The turbine comprises an outer welded casing 10, a drum or hollow shaft11 for the ahead part supporting bucket-carrying disks or wheels 12which in the present instance have been shown as being integrally formedwith the drum 11. A diaphragm 13 supported by the casing and packedagainst the shaft is interposed between adjacent bucket wheels forproperly directing the flow of elastic fluid from a higher stage to thesucceeding lower stage. The astern or reversing part comprises a stub 14which has an end portion 15 projecting into and engaging an end portionof the shaft 11. The stub 14 has an intermediate portion defining acollar 16 which with its rear face 17 bears against the end face of theshaft or drum and is fastened thereto by means of axial bolts 18. Thereversing part has a double-row bucket wheel including a disk 19 and tworows of buckets 20 and 21 respectively.

The bucket wheel in accordance with my invention is supported by boththe shaft and the stub and fastened thereto in such manner that it mayexpand relatively to the shaft and the stub without setting up unduestresses. This is accomplished by a plurality of circumferentiallyequally spaced pins projecting through radial holes or bores in thebucket wheel and at least the shaft, or through both the shaft and thestub. To secure uniform expansion and concentric relation between thevarious parts, it is necessary to provide at least three radial pinsdisplaced at 120 angular degrees.

In the drawing I have shown pins 22 projecting through radial holes inthe bucket wheel and the overlapping portions of the shaft and the stub.Each pin is prevented from sliding outward by means of a plug 23 screwedinto the hole of the wheel. The reversing part has an inlet conduit 24for elastic fluid and a diaphragm 25 for directing elastic fluid fromthe first row of buckets 20 to the second row 21. The casing is packedagainst the shaft stub by a plurality of packings 26. The outer casingand the first wheel define a chamber 27. A part of the clastic fluidconducted through conduit 24 into the turbine leaks past the entranceside of the doublerow bucket wheel into the chamber 27. To prevent thisleakage fiuid from coming into contact with the stub and excessivelyheating it, I provide in a preferred embodiment the entrance side of thebucket wheel with an inwardly projectin? disk portion 28 which near itsinner circumference engages the front face 29 of the collar. The diskportion 28 also reinforces the bucket wheel.

During operation of the reversing part the bucket wheel thereof mayexpand freely in radial direction. Uniform expansion and eccentricrelation between the bucket Wheel, the shaft and the stub are maintainedby the radial pins. Excessive heating of the stub is prevented by theinwardly projecting disk portion of the bucket wheel.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is,

1. In a reversing turbine, an ahead and an astern part with a commonexhaust casing for both, a bucket wheel for the ahead part, a shaft foreach part, the shafts having portions overlapping each other, a bucketwheel for the astern part, and at least three circumferentially spacedpins projecting through radial holes in the shaft and the last namedbucket wheel for permitting relative expansion and at the same timemaintaining concentric relation between said wheel and the shaft.

2. In a reversing turbine, an ahead and an astern part with a commonexhaust casing for both, a bucket wheel for the ahead part, a shaft foreach part, the shafts having portions overlapping each other, a bucketwheel for the astern part, at least three circumferentially spaced pinssliding through radial holes in the shafts and the last named bucketwheel for permitting relative expansion and at the same time maintainingconcentric relation between said wheel and the shaft, and plugs screwedinto the holes in the wheel retaining the pins in the holes, the lastnamed bucket wheel having a portion on the entrance side of thereversing part engaging the front face of a shoulder formed on the shaftof the reversing part to prevent elastic fluid from coming into contactwith the major portion of said reversing shaft during operation of thereversing part.

3. In a reversing turbine, an ahead and an astern part with a commonexhaust casing for both, the ahead part having a hollow shaft and abucket wheel, the astern part having a stub with a portion seated withinthe hollow end portion of said shaft and a collar with a rear faceengaging the end face of the shaft, a double-row wheel of the asternpart being seated on the end portion of the shaft and the circumferenceof the collar and having a disk portion engaging the front face of thecollar, at least three circumferentially equally spaced, radial pinsprojecting into holes in the shaft and the double row bucket wheel, andaxial bolts for fastening the collar to the shaft.

JOHN H. DORAN.

